Add more control commands

[AlanCoding]

This adds the control commands:

• producers
• run
• status

Only the "producers" actually does much novel, and what it adds isn't much, because we need #126 to track more meaningful information on the producers.

The "run" command seems silly, but needs #122, so this combined with that will allow tasks to run control tasks... and one control task can... run other tasks. Put it together, this would allow tasks to run other tasks.

This is extremely demo-able

$ dispatcherctl --help
usage: dispatcherctl [-h] [--log-level {DEBUG,INFO,WARNING,ERROR,CRITICAL}] [--config CONFIG] [--task TASK] [--uuid UUID]
                     [--expected-replies EXPECTED_REPLIES]
                     {running,cancel,alive,aio_tasks,workers,producers,status}

CLI entrypoint for dispatcher, mainly intended for testing.

and

$ dispatcherctl producers
DEBUG:dispatcher.cli:Configured standard out logging at DEBUG level
INFO:dispatcher.cli:Using config from file /home/alancoding/repos/dispatcher/dispatcher.yml
INFO:awx.main.dispatch.control:control-and-reply producers to None
INFO:dispatcher.brokers.pg_notify:Set up pg_notify listening on channel 'reply_to_0e4410ea_541c_47b7_bb25_aa472084f572'
DEBUG:dispatcher.brokers.pg_notify:Sent pg_notify message of 85 chars to test_channel
DEBUG:dispatcher.brokers.pg_notify:Starting listening for pg_notify notifications
INFO:awx.main.dispatch.control:control-and-reply message returned in 0.07825517654418945 seconds
- BrokeredProducer:
    produced_count: 2
  ControlProducer:
    produced_count: 0
  OnStartProducer:
    produced_count: 1
  ScheduledProducer:
    produced_count: 20
  node_id: demo-server-a

And the dispatcher status command is nice, but its output is a bit more than I want to paste here.

[art-tapin]

It's a fantastic addition to the dispatcher! Before your latest commit, I ran tested the PR covering:

• Basic control commands (producers, status)
• Task-to-task communication (parent tasks launching child tasks)
• Multi-level task chaining (tasks launching tasks launching tasks...)
• Edge cases (error handling, timeouts, parallel execution)

Everything works as expected and the implementation is solid! LGTM ✔️

However, I did notice one integration test failing with your latest "Add test for task-from-task" commit:

tests/integration/test_disruptions.py::test_sever_pg_connection
assert 2 == 1

The issue is that test_sever_pg_connection assumes there's only one producer (assert len(apg_dispatcher.producers) == 1), but you've added ControlProducer to the default test configuration in conftest.py, which increases the count to 2.

This should be easy to fix - either update the test to not make assumptions about the exact number of producers or modify it to specifically check for the presence of the pg_notify producer.

Otherwise, the PR looks great and the documentation updates are helpful.

Approved, just don't forget about that small test issue is addressed 🤓

🥇